The present invention relates to an image processing apparatus, image processing system, and image processing method, a program, and a computer readable storage medium that stores the program, for executing an image processing for an objective image.
Conventionally, for example, a chest image obtained by X-ray photography has a very broad range of pixel values since it is made up of an image region of lungs which readily transmit X-rays, and an image region of a mediastinal part which hardly transmit X-rays. For this reason, it has been considered to be difficult to obtain a visualized X-ray chest image that allows to simultaneously observe image portions of both the lungs and mediastinal part.
As a method of avoiding this problem, an image processing method described in Japanese Patent Laid-Open No. 2000-101841 or the like is known. This image processing method is described using an original image f(x, y), an image fh(x, y) after tone conversion of the original image f(x, y), an image fc(x, y) after compression of the original image f(x, y), a low-frequency image (smoothed image) Sus(x, y) of the original image f(x, y), and a constant B by:                               fc          ⁡                      (                          x              ,              y                        )                          =                              F            ⁡                          (                              f                ⁡                                  (                                      x                    ,                    y                                    )                                            )                                +                      B            xc3x97                          (                              1                -                                                      ∂                                          F                      ⁡                                              (                                                  f                          ⁡                                                      (                                                          x                              ,                              y                                                        )                                                                          )                                                                                                  ∂                                          f                      ⁡                                              (                                                  x                          ,                          y                                                )                                                                                                        )                        xc3x97                          (                                                f                  ⁡                                      (                                          x                      ,                      y                                        )                                                  -                                  Sus                  ⁡                                      (                                          x                      ,                      y                                        )                                                              )                                                          (        1        )                                          Sus          ⁡                      (                          x              ,              y                        )                          =                                            ∫                              -                d1                            d1                        ⁢                                          ∫                                  -                  d2                                d2                            ⁢                                                f                  ⁡                                      (                                                                  x                        +                        x1                                            ,                                              y                        +                        y1                                                              )                                                  ⁢                                  xe2x80x83                                ⁢                                  ⅆ                  x1                                ⁢                                  xe2x80x83                                ⁢                                  ⅆ                  y1                                                                                        ∫                              -                d1                            d1                        ⁢                                          ∫                                  -                  d2                                d2                            ⁢                                                ⅆ                  x1                                ⁢                                  xe2x80x83                                ⁢                                  ⅆ                  y1                                                                                        (        2        )            
In equation (1),
f(x, y)xe2x88x92Sus(x, y)
represents high-frequency components. By the effect of the second term of equation (1) including this part, the amplitudes of the compressed high-frequency components are restored or reconstructed (when B=1) and, hence, the appearance of a microstructure mainly formed by the high-frequency components can be maintained as in the original image f(x, y) even after compression of the dynamic range.
Note that xe2x80x9cF( )xe2x80x9d is a monotone increasing function indicating a tone conversion curve. The tone conversion curve F( ) is defined to be continuous and differentiable. With this method, the dynamic range of image data can be compressed while maintaining the amplitudes of high-frequency components (when B=1).
Note that the low-frequency image xe2x80x9cSus(x, y)xe2x80x9d given by equation (2) is a moving average image of the original image f(x, y).
As an image process for making the microstructure easy to see, a so-called sharpening process is known. This sharpening process is described using the original image f(x, y), a processed image fp(x, y), a low-frequency image Sus2(x, y) of the original image f(x, y), and a constant C by:
fp(x, y)=f(x, y)+Cxc3x97(f(x, y)xe2x88x92Sus2(x, y))xe2x80x83xe2x80x83(3)
Note that the low-frequency image Sus2(x, y) has a mask size different from the low-frequency image Sus(x, y) given by equation (2).
As another image process, a noise removal process for reducing noise by removing or suppressing predetermined high-frequency components have been examined.
However, with the conventional image processing method, all of a plurality of image processes such as the aforementioned dynamic range compression process, sharpening process, noise removal process, and the like cannot be satisfactorily done for an original image.
More specifically, when the original image f(x, y) undergoes the sharpening process, and then the dynamic range compression process, equation (1) is rewritten as:                               fc          ⁡                      (                          x              ,              y                        )                          =                              F            ⁡                          (                              fp                ⁡                                  (                                      x                    ,                    y                                    )                                            )                                +                      B            xc3x97                          (                              1                -                                                      ∂                                          F                      ⁡                                              (                                                  f                          ⁡                                                      (                                                          x                              ,                              y                                                        )                                                                          )                                                                                                  ∂                                          f                      ⁡                                              (                                                  x                          ,                          y                                                )                                                                                                        )                        xc3x97                          (                                                fp                  ⁡                                      (                                          x                      ,                      y                                        )                                                  -                                  Sus3                  ⁡                                      (                                          x                      ,                      y                                        )                                                              )                                                          (        4        )            
In this equation (4),
fp(x, y)xe2x88x92Sus3(x, y)
represents the high-frequency components of the image fp(x, y) after the sharpening process.
However, the low-frequency image Sus3(x, y) of the image fp(x, y) after the sharpening process is influenced by the term including xe2x80x9cSus4(x, y)xe2x80x9d, as described by:                                                                         Sus3                ⁡                                  (                                      x                    ,                    y                                    )                                            =                            ⁢                                                                    ∫                                          -                      d1                                        d1                                    ⁢                                                            ∫                                              -                        d2                                            d2                                        ⁢                                                                  fp                        ⁡                                                  (                                                                                    x                              +                              x1                                                        ,                                                          y                              +                              y1                                                                                )                                                                    ⁢                                              xe2x80x83                                            ⁢                                              ⅆ                        x1                                            ⁢                                              xe2x80x83                                            ⁢                                              ⅆ                        y1                                                                                                                                  ∫                                          -                      d1                                        d1                                    ⁢                                                            ∫                                              -                        d2                                            d2                                        ⁢                                                                  ⅆ                        x1                                            ⁢                                              xe2x80x83                                            ⁢                                              ⅆ                        y1                                                                                                                                                                    =                            ⁢                                                                    (                                          1                      +                      c                                        )                                    xc3x97                                      Sus                    ⁡                                          (                                              x                        ,                        y                                            )                                                                      -                                  c                  xc3x97                                      Sus4                    ⁡                                          (                                              x                        ,                        y                                            )                                                                                                                              (        5        )                                          Sus4          ⁡                      (                          x              ,              y                        )                          =                                            ∫                              -                d1                            d1                        ⁢                                          ∫                                  -                  d2                                d2                            ⁢                                                sus2                  ⁡                                      (                                                                  x                        +                        x1                                            ,                                              y                        +                        y1                                                              )                                                  ⁢                                  xe2x80x83                                ⁢                                  ⅆ                  x1                                ⁢                                  xe2x80x83                                ⁢                                  ⅆ                  y1                                                                                        ∫                              -                d1                            d1                        ⁢                                          ∫                                  -                  d2                                d2                            ⁢                                                ⅆ                  x1                                ⁢                                  xe2x80x83                                ⁢                                  ⅆ                  y1                                                                                        (        6        )            
and is different from high-frequency components given by:
f(x, y)xe2x88x92Sus(x, y)
in equation (1), and high-frequency components given by:
fp(x, y)xe2x88x92Sus3(x, y)
in equation (4).
Therefore, the dynamic range compression process described by equation (1), and that described by equation (4) have different high-frequency bands to be restored and different restorabilities of the microstructure, and such differences may deteriorate image quality. The same problem is experienced when the sharpening process is done after the dynamic range compression process.
That is, when a frequency process using a low-frequency image obtained by calculating a moving average or the like is done twice or more, the same problem is posed irrespective of what sharpening and dynamic range compression processes are used. Since the visible characteristics of a human being for high-frequency components change depending on the density (luminance) level, and the dynamic range compression process changes the density (pixel value) level of at least a partial region of an image, the effect of the sharpening process is influenced by the dynamic range compression process.
The noise removal process basically suppresses high-frequency components, while the sharpening process emphasizes high-frequency components. That is, the noise removal process and sharpening process have conflicting effects.
Therefore, in a conventional arrangement in which the noise removal process and sharpening process are independently done, a region where high-frequency components are to be suppressed may be emphasized, or a region where high-frequency components are to be emphasized may be suppressed. Such problem directly leads to deterioration of image quality.
Also, the sharpening process described by equation (3) cannot emphasize a specific frequency band (e.g., one or a plurality of predetermined middle frequency bands). Hence, an image process such as a sharpening process may be executed using a multiple-frequency process that can easily adjust (emphasize and/or suppress) the specific frequency band). In this case as well, the same problem as described above remains unsolved upon executing a plurality of different image processes such as a process for changing the dynamic range, sharpening process, and the like.
For example, a plurality of different image processes such as a dynamic range change process, sharpening process, and the like must be appropriately mixed to assure restorability of image components in a specific frequency band or allow an easy frequency emphasis or suppression process that the user intended.
The present invention has been made to solve the above problems, and has as its object to provide an image processing apparatus, image processing system, and image processing method, a program, and a computer readable storage medium that stores the program, which can systematically, efficiently, and appropriately execute a plurality of image processings.
It is another object of the present invention to provide an image processing apparatus, image processing system, and image processing method, a program, and a computer readable storage medium that stores the program, which can obtain a stable image processing effect.
In order to achieve the above objects, an image processing apparatus according to the present invention comprises the following arrangement. That is, there is provided an image processing apparatus for executing a plurality of image processes for an objective image, comprising:
a decomposition unit for decomposing the objective image into components of a plurality of frequency bands;
an analysis unit for analyzing the components obtained by the decomposition unit with respect to each of the plurality of image processings;
a component conversion unit for converting the components obtained by the decomposition unit on the basis of analysis results of the analysis unit; and
an image generation unit for generating an image, after the objective image has undergone the plurality of image processings, from the components of the plurality of frequency bands converted by the component conversion unit.
Preferably, the plurality of image processes include at least two of a noise removal process, sharpening process, and dynamic range change process.
Preferably, the objective image includes an image taken by radiography.
In order to achieve the above objects, an image processing apparatus according to the present invention comprises the following arrangement. That is, there is provided an image processing apparatus for executing a plurality of image processings for an objective image, comprising:
a decomposition unit for decomposing the objective image into components of a plurality of frequency bands;
an analysis unit for analyzing the components obtained by the decomposition unit with respect to each of the plurality of image processings on the basis of information of a pixel value level of a visible image obtained via the plurality of image processings for the objective image;
a component conversion unit for converting the components obtained by the decomposition unit on the basis of analysis results of the analysis unit; and
an image generation unit for generating an image, after the objective image has undergone the plurality of image processings, from the components of the plurality of frequency bands converted by the component conversion unit.
Preferably, the plurality of image processes include at least two of a noise removal process, sharpening process, and dynamic range change process.
Preferably, the objective image includes an image taken by radiography.
Preferably, the apparatus further comprises tone conversion unit for converting an input pixel value into a pixel value of the visible image, and
the component conversion unit converts the components obtained by the decomposition unit on the basis of tone conversion characteristics of the tone conversion unit.
Preferably, the component conversion unit converts the components obtained by the decomposition unit on the basis of the tone conversion characteristics and pattern information which specifies a relationship between the pixel value level and component conversion characteristics of the component conversion unit.
Preferably, the component conversion unit is noise removal means, and
the component conversion unit changes a cutoff width of a coefficient conversion curve for noise removal on the basis of the information of the pixel value level.
Preferably, the objective image is an image taken by radiography of an object, and
the pattern information is determined based on at least one information of a portion to be radiographed of the object and a condition of the radiography.
Preferably, the apparatus further comprises change unit for changing the tone conversion characteristics.
In order to achieve the above objects, an image processing apparatus according to the present invention comprises the following arrangement. That is, there is provided an image processing apparatus for executing an image process for an objective image, comprising:
a decomposition unit for decomposing the objective image into components of a plurality of frequency bands;
a component conversion unit for converting the components obtained by the decomposition unit on the basis of information of a pixel value level of a visible image obtained via the image processing for the objective image; and
an image generation unit for generating an image, after the objective image has undergone the image processings, from the components of the plurality of frequency bands converted by the component conversion unit.
Preferably, the apparatus further comprises a tone conversion unit for converting an input pixel value into a pixel value of the visible image, and
the component conversion unit converts the components obtained by the decomposition unit on the basis of tone conversion characteristics of the tone conversion unit.
Preferably, the component conversion unit converts the components obtained by the decomposition unit on the basis of the tone conversion characteristics and pattern information which specifies a relationship between the pixel value level and component conversion characteristics of the component conversion unit.
Preferably, the component conversion unit has a noise removal function, and
the component conversion unit changes a cutoff width of a coefficient conversion curve for noise removal on the basis of the information of the pixel value level.
Preferably, the objective image is an image taken by radiography of an object, and
the pattern information is determined based on at least one information of a portion to be radiographed of the object and a condition of the radiography.
Preferably, the apparatus further comprises a change unit for changing the tone conversion characteristics.
In order to achieve the above objects, an image processing system according to the present invention comprises the following arrangement. That is, there is provided an image processing system formed by connecting a plurality of apparatuses intercommunicatably for executing a plurality of image processings for an objective image, comprising:
a decomposition unit for decomposing the objective image into components of a plurality of frequency bands;
an analysis unit for analyzing the components obtained by the decomposition unit with respect to each of the plurality of image processings;
a component conversion unit for converting the components obtained by the decomposition unit on the basis of analysis results of the analysis unit; and
an image generation unit for generating an image, after the objective image has undergone the plurality of image processings, from the components of the plurality of frequency bands converted by the component conversion unit.
In order to achieve the above objects, an image processing system according to the present invention comprises the following arrangement. That is, there is provided an image processing system formed by connecting a plurality of apparatuses intercommunicatably for executing a plurality of image processings for an objective image, comprising:
a decomposition unit for decomposing the objective image into components of a plurality of frequency bands;
an analysis unit for analyzing the components obtained by the decomposition unit with respect to each of the plurality of image processings on the basis of information of a pixel value level of a visible image obtained via the plurality of image processings for the objective image;
a component conversion unit for converting the components obtained by the decomposition unit on the basis of analysis results of the analysis unit; and
an image generation unit for generating an image, after the objective image has undergone the plurality of image processings, from the components of the plurality of frequency bands converted by the component conversion unit.
In order to achieve the above objects, an image processing system according to the present invention comprises the following arrangement. That is, there is provided an image processing system formed by connecting a plurality of apparatuses intercommunicatably for executing an image processings for an objective image, comprising:
a decomposition unit for decomposing the objective image into components of a plurality of frequency bands;
a component conversion unit for converting the components obtained by the decomposition unit on the basis of information of a pixel value level of a visible image obtained via the image processing for the objective image; and
an image generation unit for generating an image, after the objective image has undergone the image processings, from the components of the plurality of frequency bands converted by the component conversion unit.
In order to achieve the above objects, a program according to the present invention comprises the following arrangement. That is, there is provided a program for making a computer function as an image processing apparatus for executing a plurality of image processing for an objective image,
the image processing apparatus comprising:
a decomposition unit for decomposing the objective image into components of a plurality of frequency bands;
an analysis unit for analyzing the components obtained by the decomposition unit with respect to each of a plurality of image processes;
a component conversion unit for converting the components obtained by the decomposition unit on the basis of analysis results of the analysis unit; and
an image generation unit for generating an image, after the objective image has undergone the plurality of image processings, from the components of the plurality of frequency bands converted by the component conversion unit.
In order to achieve the above objects, a program according to the present invention comprises the following arrangement. That is, there is provided a program for making a computer function as an image processing apparatus for executing a plurality of image processing for an objective image,
the image processing apparatus comprising:
a decomposition unit for decomposing the objective image into components of a plurality of frequency bands;
an analysis unit for analyzing the components obtained by the decomposition unit with respect to each of the plurality of image processings on the basis of information of a pixel value level of a visible image obtained via the plurality of image processings for the objective image;
a component conversion unit for converting the components obtained by the decomposition unit on the basis of analysis results of the analysis unit; and
an image generation unit for generating an image, after the objective image has undergone the plurality of image processings, from the components of the plurality of frequency bands converted by the component conversion unit.
In order to achieve the above objects, a program according to the present invention comprises the following arrangement. That is, there is provided a program for making a computer function as an image processing apparatus for executing an image processing for an objective image,
the image processing apparatus comprising:
a decomposition unit for decomposing the objective image into components of a plurality of frequency bands;
a component conversion unit for converting the components obtained by the decomposition unit on the basis of information of a pixel value level of a visible image obtained via the image processing for the objective image; and
an image generation unit for generating an image, after the objective image has undergone the plurality of image processings, from the components of the plurality of frequency bands converted by the component conversion unit.
In order to achieve the above objects, a computer readable medium according to the present invention comprises the following arrangement. That is, there is provided a computer readable storage medium which stores a program for making a computer function as an image processing apparatus for executing an image processing for an objective image,
the image processing apparatus comprising:
a decomposition unit for decomposing the objective image into components of a plurality of frequency bands;
an analysis unit for analyzing the components obtained by the decomposition unit with respect to each of the plurality of image processings;
a component conversion unit for converting the components obtained by the decomposition unit on the basis of analysis results of the analysis unit; and
an image generation unit for generating an image, after the objective image has undergone the plurality of image processings, from the components of the plurality of frequency bands converted by the component conversion unit.
In order to achieve the above objects, a computer readable medium according to the present invention comprises the following arrangement. That is, there is provided a computer readable storage medium which stores a program for making a computer function as an image processing apparatus for executing a plurality of image processings for an objective image,
the image processing apparatus comprising:
a decomposition unit for decomposing the objective image into components of a plurality of frequency bands;
an analysis unit for analyzing the components obtained by the decomposition unit with respect to each of the plurality of image processings on the basis of information of a pixel value level of a visible image obtained via the plurality of image processings for the objective image;
a component conversion unit for converting the components obtained by the decomposition unit on the basis of analysis results of the analysis unit; and
an image generation unit for generating an image, after the objective image has undergone the plurality of image processings, from the components of the plurality of frequency bands converted by the component conversion unit.
In order to achieve the above objects, a computer readable medium according to the present invention comprises the following arrangement. That is, there is provided a computer readable storage medium which stores a program for making a computer function as an image processing apparatus for executing an image processing for an objective image,
the image processing apparatus comprising:
a decomposition unit for decomposing the objective image into components of a plurality of frequency bands;
a component conversion unit for converting the components obtained by the decomposition unit on the basis of information of a pixel value level of a visible image obtained via the image processing for the objective image; and
an image generation unit for generating an image, after the objective image has undergone the plurality of image processings, from the components of the plurality of frequency bands converted by the component conversion unit.
In order to achieve the above objects, an image processing method according to the present invention comprises the following arrangement. That is, there is provided an image processing method of executing a plurality of image processings for an objective image, comprising:
the decomposition step of decomposing the objective image into components of a plurality of frequency bands;
the analysis step of analyzing the components obtained in the decomposition step with respect to each of the plurality of image processings;
the component conversion step of converting the components obtained in the decomposition step on the basis of analysis results of the analysis step; and
the image generation step of generating an image, after the objective image has undergone the plurality of image processings, from the components of the plurality of frequency bands converted in the component conversion step.
In order to achieve the above objects, an image processing method according to the present invention comprises the following arrangement. That is, there is provided an image processing method of executing a plurality of image processings for an objective image, comprising:
the decomposition step of decomposing the objective image into components of a plurality of frequency bands;
the analysis step of analyzing the components obtained in the decomposition step with respect to each of the plurality of image processings on the basis of information of a pixel value level of a visible image obtained via the plurality of image processings for the objective image;
the component conversion step of converting the components obtained in the decomposition step on the basis of analysis results of the analysis step; and
the image generation step of generating an image, after the objective image has undergone the plurality of image processings, from the components of the plurality of frequency bands converted in the component conversion step.
In order to achieve the above objects, an image processing method according to the present invention comprises the following arrangement. That is, there is provided an image processing method of executing an image processing for an objective image, comprising:
the decomposition step of decomposing the objective image into components of a plurality of frequency bands;
the component conversion step of converting the components obtained in the decomposition step on the basis of information of a pixel value level of a visible image obtained via the image processing for the objective image; and
the image generation step of generating an image, after the objective image has undergone the plurality of image processings, from the components of the plurality of frequency bands converted in the component conversion step.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.